Paper bag



Dec. 7, 1943- 1.. COAKLEY ETAL PAPER BAG Filed Jan. 6 1941 [/65 COAKLEY F PM MN Patented Dec. 7, 1943 PAPER BAG Lige Coakley, East Pepper-ell, Mass, and Harold V. Kindseth, Minneapolis, Minn., assignors to Bemis Bro.Bag 00., Minneapolis, Min, a corporation of Missouri Application January 6, 1941, Serial No. 373,212

1 Claim.

This invention relates to new and useful improvements in paper bags, and more particularly to such bags used in the packaglng'of hydroscopic materials such, for example, as sugar.

In the packaging of sugar and other similar products. it is important that the walls of the container in which the sugar is packaged, is so constructed or treated that moisture cannot penetrate therethrough and contact the contents of the bag when the bag i filled, as moistur has a tendency to cause portions of the sugar to harden and become lumpy, in which form it may adhere to the wallsof the bag.

Paper bags, when closed and sealed, usually have a suitable paste applied to one or more of the bag top walls before the bag top walls are folded into closing and sealing relation. Commercial paste, such as commonly used for securing together the bag top walls, may contain a relatively high percentage of moisture. moisture, because of the inherent porosity of the paper stock from which the bags are made, may penetrate the bag top walls, which obviously, is objectionable when the bags are filled with sugar or some other hydroscopic material of a similar nature.

To prevent the moisture from penetrating through the walls of the bag top, we propose to apply a suitable water-proof agent to one or more of the bag top walls in such a. manner that when the bag top walls are folded into closing and sealing relation, said water-proof agent will be interposed between the contents of the bag and the paste applied to the walls thereof to seal the bag top, whereby the moisture of the paste cannot contact the sugar or 'Other contents of th bag. The present invention distinguishes from the invention disclosed in our pending application, Serial Number 240,- 628, filed November 16, 1938, now matured into Patent No. 2,230,998, in that the water-proof agent is applied directly to the inner surface of one or more of the bag top walls, whereas the above noted application is directed more specifically to the application of a water-proof agent to multi-ply walls, and wherein the water-proofing is interposed between the plies of the bag walls. The present invention is directed to the application of a suitable water-proof agent to bags or containers made from singl ply sheet material. 3

The water-proofing may be in the form of a thin sheet of rubberized material, such as latex,

which may be applied directly to the inner surface of one or more of the bag top walls, where- Thisby it will be interposed between the contents of the bag and the paste applied to the bag top walls to secure them in sealing relation. In some instances, it may be found more desirable to apply the water-proofing in the form of liquid, whereby it will form a moisture-proof coating on the bag top walls.

Other objects of the invention will appear from the following description and accompanying drawing and will be pointed out in the annexed claim.

In the accompanying drawing there has been disclosed a structure designed to carry out the various objects of the invention, but it is to be understood that the invention is not confined to the exact features shown, as various changes may be made within the scope of the claim which follows.

In the drawing:

Figure 1 is a perspective view showing the upper portion of a filled bag with the water-proof agent applied to the inner surface of one of the end walls of the bag mouth;

Figure 2 is a detail sectional view showing an empty bag prior to filling;

Fi ure 3 is a view showing one of the end walls of the bag top inwardly folded over the contents of the bag with the water-proof agent interposed between the contents of the bag and said end wall;

Figur 4 is a plan view of a closed bag top;

and

Figure 5 is a side elevation of the upper portion-of a filled closed bag, partially broken away to more clearly illustrate the location of the water-proof agent between th paste and the contents of the bag.

In the selected embodiment of the invention herein disclosed, there is illustrated in Figure 3.

for purposes of disclosure, 8. bag comprising side walls 2 and 3, and end walls 4 and 5. The upper portions of these walls cooperate to define the mouth of the bag, as clearly illustrated in Figure 1. The bag shown in Figures 1 and 3 is preferably constructed of a suitabl single ply material, such as used in the bag industry, and is made in the form of a tube, as shown in Figure 2, having a seam 6 securing together the overlapping edges of the sheet material from which the tube is made. I

An important feature of the present invention resides in the application of a suitable waterproof agent, generally designated by the numeral I, to one or more of the bag top walls. In Figure 1 the water-proofing I is shown er plied to the upp r Portion of the end wall 4, and partially extends around onto the side Walls 2 and 3, as shown at 8 in Figure 1. The waterproofing may be in the form of a thin sheet of rubberized material, such as latex, which may be applied directly to the inner surface of the bag mouth wall by the application of heat or in some other suitable manner. It may also be applied thereto in the form of a liquid.

In the accompanying drawing, we have shown the invention applied to a bag 'top having a Deltaseal closure; Obviously, it may be ap plied to other types of closures without departing from the scope of the invention. The waterproofing I is applied to the wall which is first folded inwardly over the contents of the bag, in the operation of closing the bag top which, in the present instance, is the end wall 4. When this end wall is inwardly folded over the contents of the bag, as shown in Figure 3, a suitable paste or adhesive, indicated by the numeral 9, is applied to the upper exposed surface of the inwardly folded end wall 4, and the oppositely disposed end wall may then be folded inwardly over the end wall 4, whereby oppositely extending flaps I i and I! are provided, as indicated by the dotted lines in Figures 3 and 4. The flaps H and I2 are subsequently folded inwardly over the previously folded end walls 4 and 5, as shown in Figure 4, andsuitably secured together by such means as paste.

When the bag top is thus sealed, the waterproofing is interposed between the contents of the bag body and the paste 9, as will readily be understood by reference to Figures 3 and 5, thereby positively preventing moisture in the paste from contacting .the contents of the bag. The area coated with water-"proofing is relatively larger than the paste or gummed area 9, as clearly illustrated in Figures 3 and 5, whereby moisture in the paste is not likely to creep around the edges of the water-proof agent and contact the contents of the bag.

The water-proofing may readily be applied to the bag top walls in the operation of making the bag blanks, whereby it does not materially increase the cost of the bags. It is to be understood that the coating of water-proofing applied to the inner surface of the bag top wall is very thin and flexible, whereby it does not stifien the wall to which it is applied and thereby interfere with the folding of the bag top walls into closing relation. Any suitable water-proof material which will serve the purpose may be utilized without departing from the scope of the invention. It is also to be understood that the present invention is not limited to the application of a water-proof agent to single-ply walls, as obviously the water-proofing could be applied to the inner surfaces of multi-ply walls with equal results.

We claim as our invention:

A bag made from a tube of porous non-moisture-proof material, one end of said tube being closed to provide the bottom of the bag and the top wall portions at the opposite end of the tube being adapted to be folded into closing and sealing relation and bonded together by a suitable paste to close the bag top after the bag has been filled, and a water-proof material applied to the inner exposed surface of a section only of the top wall portion, said section extending about approximately one fourth the perimeter of the top LIGE COAIQLEY.

. HAROLD V. KINDSETH. 

